A powder paint having a form in which a vinyl polymer which contains an epoxy group is used as the resin component and a polycarboxylic acid compound is used as the hardening agent component is used in a wide range of applications because it can form a paint coating which is particularly superior in weather resistance.
However, this type of powder paint has the disadvantage of being inferior in mar resistance and the like, and when attempts are made to improve this mar resistance and the like, the appearance and the like of the paint coating become easily degraded, as a result, it is difficult to obtain a balance of all properties.
Furthermore, when powder paint is applied to a base-coat layer formed by the application of a water-based paint, smoothness of the paint and the like are seriously impaired, defects in the paint coating, such as orange peel, craters, pinholes and the like, are produced. As a result, in reality, it is only possible to obtain a paint coating which is very unsatisfactory from the point of view of the balance of properties of appearance and mar resistance.
In this way, in line with the limitations of conventional techniques as described above, it has been virtually impossible to realize a powder paint composition, and an application method for this composition, which has extremely high utility, is superior in the mar resistance and the like of the paint coating, is superior in the appearance of the paint coating and, in addition, is also superior in the smoothness and sharpness of the paint coating.
In addition, even in situations when a powder paint has been applied to a so called water-based base-coat layer, in which a water-based base-coat paint coating is applied, it has been virtually impossible to realize a powder paint composition, and application method therefor, which has extremely high utility, and which gives this type of paint coating which has a balance of both properties of appearance and mar resistance.
Nevertheless, the inventors of the present invention began research in earnest in order to realize the establishment of a powder paint composition, and an application method for this composition, which has extremely high utility, and for which the mar resistance and the like of the paint coating is superior, the appearance and the like of the paint coating is superior and, in addition, the smoothness and sharpness of the paint coating is superior even when the powder paint is applied to a water-based base-coat layer.
Consequently, the problem solved by the present invention is the provision of a powder paint composition which has extremely high utility, which achieves a balance of both properties of mar resistance and appearance of the paint coating in particular and, of course, which is superior in the sharpness and smoothness of the paint coating; and the provision of an application method for this composition.